Elevation is a measurement used to determine height and depth. In geography, elevation is usually measured in relation to sea level. The tallest location on the Earth is Mt.Everest at 8,848m above sea level. In Louisiana, the lowest area of land is actually 8 feet below sea level, and the highest elevation is 535 feet above sea level. The coast of Louisiana is always changing. Much of the coastal wetlands are being flooded because the elevation of the land continues to drop. The levees are used to prevent flooding in areas where people live, which is why some areas of Louisiana are below sea level.